1. Field of the Invention
The present invention relates to a hermetic compressor and, more particularly, to a hermetic compressor capable of preventing malfunction or operation stoppage thereof by impurities trapped between contact surfaces of a crankshaft, which is mounted in the compressor to generate a driving force, and a crankshaft supporting frame.
2. Description of the Related Art
FIG. 1 is a side sectional view of a conventional hermetic compressor. As shown in FIG. 1, the hermetic compressor, that is generally employed in a refrigeration cycle of a refrigerator, air conditioner, etc., comprises a hermetic container 1 forming the outer appearance thereof, a compression unit 50 mounted in the hermetic container 1 to compress a refrigerant, and a drive unit 10 to generate a compressive force required to compress the refrigerant in the compression unit 50. The hermetic container 1 is provided at certain locations thereof with a suction tube to guide the exterior refrigerant into the hermetic container, and a discharge tube to discharge the refrigerant, compressed in the compression unit, out of the hermetic container.
Specifically, the drive unit 10 includes a crankshaft 16, a rotor 12, a stator 14, and an eccentric unit 32. The crankshaft 16 serves to transmit the driving force of the drive unit 10 to the compression unit 50 as it rotates. The rotor 12 generates a rotating force required to rotate the crankshaft 16, and the stator 14 is positioned to electromagnetically interact with the rotor 12. The eccentric unit 32 is provided at one end of the crankshaft 16 to create an eccentric motion. The eccentric unit 32 includes an eccentric shaft 28 fitted on the crankshaft 16, and a balance weight 30 to compensate the eccentric motion.
Provided in the crankshaft 16 are an internal passage 18 and an impeller 19, which are used to raise oil stored in a lower region of the hermetic container 1. A plurality of oil holes 20 and 24 are formed at an outer circumferential surface of the crankshaft 16 to be in communication with the internal passage 18. The oil holes 20 and 24 are connected to each other through an external passage 22. The external passage 22 is formed in the outer circumferential surface of the crank shaft 16 to extend in a rotating direction of the crankshaft 16.
FIG. 2 is a perspective view showing the coupling structure of the crankshaft and a supporting frame therefor. As shown in FIG. 2, the crankshaft 16 is inserted in a hollow portion of a frame 34 to be supported by a thrust portion 36 of the frame 34. The crankshaft 16 is adapted to rotate while maintaining a very minute spacing between the outer circumferential surface thereof and the thrust portion 36. During rotation of the crankshaft 16, the oil, raised from the lower region of the hermetic container 1, acts to lubricate between the crankshaft 16 and the thrust portion 36 of the frame 34.
A problem of the above-described compressor is that no passage is formed at part of the outer circumferential surface of the crankshaft 16 adjacent to the thrust portion 36 of the frame 34 and at the thrust portion 36 of the frame 34. With this configuration, even if impurities, which are mixed with the oil during lubricating operation thereof, chips created during processing of the frame 34 or the crankshaft 16, or other welding impurities, are trapped between the outer circumferential surface of the crankshaft 16 and the thrust portion 36 of the frame 34 along with the oil, the compressor is incapable of discharging them, causing stoppage in the rotating motion of the crankshaft 16. This consequently causes operation stoppage of the compressor.